ABSTRACT
@#Objective To verify the applicability of Lowry2 method[the second method of Folin-phenol method of Chinese Pharmacopoeia(VolumeⅢ,2020 edition)]for the determination of protein content of intermediate products of component pertussis vaccine.Methods The standard and sample were precipitated and pretreated with deoxycholate and trichloroacetic acid to remove impurities,and then reacted with Folin-phenol,and the absorbance was measured at 750 nm wavelength.The standard curve was drawn with the concentration and absorbance of the standard,and the sample concentration was calculated. The method was verified for the specificity,linearity,accuracy and precision,and used to detect the protein content of intermediate products of three batches of component pertussis vaccine.Results There was no significant difference between the protein content in background buffer of intermediate product detected by this method and that in ultrapure water(t = 0. 277～1. 178,P = 0. 304～0. 795);The linear relationship of standard curve was good at the protein concentration of 0～50 μg/mL,each R~2> 0. 98;The spike recovery of accuracy verification was in the range of 90%～110%;The RSDs of repeatability and intermediate precision verification were both less than 3%. The detection results of protein content in the intermediate products of three batches of component pertussis vaccine all met the requirements of internal manufacturing and verification regulations.Conclusion Lowry2 method has good specificity,accuracy and precision,and can be used to determine the protein content of component pertussis intermediate products,which provides a basis for the applicability of Lowry2 method.